scanservice.java

JAVA的一些基础教程

import java.net.*;
import java.io.*;
public class ScanService {
	public static void main(String[] args) {
		String host = "localhost";
		if (args.length > 0) {
			host = args[0];
		}
		for (int i = 1; i < 1024; i++) {
			try {
				Socket s = new Socket(host, i);
				System.out.println("有程序在" + host + "上侦听"
				+ i + "端口");
			}
			catch (UnknownHostException e) {
				System.err.println(e);
				break;
			}
			catch (IOException e) {
				// 没有程序在该端口侦听
			}
		} 
	} 
}